Plasma display panel including frameless EMI filter, and/or method of making the same

ABSTRACT

A plasma display panel (PDP) includes a frameless EMI filter supported by a glass substrate for blocking/shielding substantial amounts of electromagnetic waves, with the filter being supported by a side of the substrate opposite a viewer. In certain example embodiments, the PDP filter includes a transparent conductive coating (TCC) for electromagnetic interference (EMI) and near infrared (NIR) blocking without the need for a conductive, peripheral buss bar. Additionally, in certain example embodiments, the need for a conductive frame is reduced or eliminated. The filter has high visible transmission, and is capable of blocking/shielding electromagnetic waves.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of each of application Ser.No. 12/230,033 filed Aug. 21, 2008 now U.S. Pat. No. 7,713,633 and Ser.No. 12/230,034, filed Aug. 21, 2008, the entire contents of each ofwhich are hereby incorporated herein by reference.

FIELD OF THE INVENTION

Certain example embodiments of this invention relate to a plasma displaypanel (PDP) including a filter supported by a glass substrate forblocking/shielding substantial amounts of electromagnetic waves, withthe filter being supported by a side of the substrate opposite a viewer.More particularly, certain example embodiments relate to a PDP filterthat includes a transparent conductive coating (TCC) for electromagneticinterference (EMI) and near infrared (NIR) blocking without the need fora conductive, peripheral buss bar. Additionally, in certain exampleembodiments, the need for a conductive frame is reduced or eliminated.The filter has high visible transmission, and is capable ofblocking/shielding electromagnetic waves. Certain example embodiments ofthis invention also provide methods of making the same.

BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION

Image display devices are being widely used in a variety ofapplications, including TV screens, monitors of personal computers, etc.The plasma display panel (PDP) is gaining popularity as anext-generation display device to replace the CRT because a PDP is thinand a large screen can be readily fabricated with a plurality of units.A PDP includes a plasma display panel on which an image is displayedusing a gas discharge phenomenon, and exhibits superior displaycapabilities, including high display capacity, high brightness, highcontrast, clear latent image, a wide viewing angle, etc. In a PDPapparatus, when a direct current (DC) or alternating current (AC)voltage is applied to electrodes, a discharge of gas plasma is created,resulting in the emission of ultraviolet (UV) light. The UV emissionexcites adjacent phosphor materials, resulting in electromagneticemission of visible light. Despite the above advantages, PDPs faceseveral challenges associated with driving characteristics, including anincrease in electromagnetic wave radiation, near-infrared emission, andphosphor surface reflection, and an obscured color purity due to orangelight emitted from helium (He), neon, or xenon (Xe) used as a sealinggas.

Some believe that the electromagnetic waves and near-infrared raysgenerated in PDPs may adversely affect human bodies and causemalfunctions of precision machines such as wireless telephones or remotecontrollers (e.g., see U.S. 2006/0083938, incorporated herein byreference). These waves, taken individually or collectively, may bereferred to as electromagnetic interference (EMI). Thus, in order tomake use of such PDPs, there is a desire to reduce the electromagneticwaves and near-infrared (IR or NIR) rays emitted from the PDPs to apredetermined level or less. In this respect, various PDP filters havebeen proposed for shielding electromagnetic waves or near-infrared raysemitted from the PDPs, reducing reflection of light and/or enhancingcolor purity. The proposed PDP filters are also required to meettransmittance requirements because the filters are installed on a frontsurface of each of the PDPs.

In order to reduce the electromagnetic waves and NIR waves emitted fromplasma display panels to a predetermined level or less, various PDPfilters have been used for the purposes of, for example, shieldingelectromagnetic waves or NIR emitted from the PDPs, reducing reflectionof light and/or enhancing color purity. High transmittance is requiredfor such filters because they are generally applied to the front surfaceof PDPs. Typical electromagnetic wave shielding filters meeting suchrequirements and characteristics are classified into a metalmesh-pattern filter and a transparent conductive film filter. Althoughthe metal mesh-pattern filter exhibits a good electromagnetic waveshielding effect, it has several disadvantages including poortransmittance, image distortion, and an increase in the production costdue to a costly mesh. Due to such disadvantages, electromagnetic waveshielding filters using transparent conductive films are being widelyused instead of the metal mesh-pattern filter. The transparentconductive film is generally formed of a multi-level thin film structurein which a metal film and a high-refractive-index transparent thin layerare sandwiched. Silver or a silver-based alloy may be used as the metalfilm. However, conventional PDP EMI filters tend to lack durabilityand/or can stand to be improved upon with respect to visibletransmission and/or shielding properties.

Moreover, certain PDP EMI filters need to be heat treated (e.g.,thermally tempered). Such heat treatment typically requires the use oftemperature(s) of at least 580 degrees C., more preferably of at leastabout 600 degrees C. and still more preferably of at least 620 degreesC. The terms “heat treatment” and “heat treating” as used herein meanheating the article to a temperature sufficient to achieve thermaltempering and/or heat strengthening of the glass inclusive article. Thisdefinition includes, for example, heating a coated article in an oven orfurnace at a temperature of at least about 550 degrees C., morepreferably at least about 580 degrees C., more preferably at least about600 degrees C., more preferably at least about 620 degrees C., for asufficient period to allow tempering and/or heat strengthening. Ingeneral, heat treating may be accomplished at temperatures of about 550degrees C. to about 650 degrees C. In certain instances, the HT may befor at least about 4 or 5 minutes. The use of such high temperatures(e.g., for 5-10 minutes or more) often causes coatings to break downand/or causes one or more of the aforesaid desirable characteristics tosignificantly deteriorate in an undesirable manner. Conventional PDP EMIfilters tend to suffer from a lack of thermal stability and/ordurability upon heat treatment (HT). In particular, heat treatment tendsto cause conventional PDP filters to break down.

In view of the above, there exists a need in the art for an improved PDPfilter which is improved (with respect to conventional PDP EMI filters)with respect to one or more of: (i) improved chemical durability, (ii)improved thermal stability (e.g., upon optional heat treatment such astempering), (iii) improved visible transmission, and/or (iv) improvedEMI shielding properties.

To overcome these and/or other disadvantages, attempts have been made bythe assignee of the instant invention to use a transparent conductivecoating (TCC) as an EMI filter as described, for example, in ApplicationSer. No. 61/071,936, the entire contents of which are herebyincorporated herein by reference. FIGS. 14( a)-14(c) provide an exampleview of how a PDP filter may be arranged with reference to a front coverglass. More particularly, FIG. 14( a) is a cross sectional view of theEMI filter, front cover glass, and black and silver frit frames for useat the front of a PDP panel, FIG. 14( b) is a front or viewer's view ofthe EMI filter and black frit frame for use at the front of a PDP panel,and FIG. 14( c) is a rear or plasma view of the EMI filter and black andsilver frit frames for use at the front of a PDP panel. As shown inthese figures, a front cover glass 142 is provided. Black frit 144 andsilver frit 146 are applied to the front cover glass 142 on the majorsurface thereof opposite the viewer, and they form the frames shown inFIGS. 14( b) and 14(c). Thus, the black frit 144 is visible from theviewer's side of the of the PDP panel, whereas the silver frit 146 issubstantially hidden from the viewer's side of the PDP panel, as shownin FIG. 14( b). By contrast, both the silver frit 146 and the black frit144 are visible from the plasma side of the PDP panel, as shown in FIG.14( c), because of how and where the silver frit 146 is applied inrelation to the black frit 144. As will be appreciated from FIGS. 14( b)and 14(c), the black frit 144 and the silver frit 146 are both providedaround the periphery of the glass substrate 142, although the black frit144 extends around and/or helps to conceal the silver frit 146 whenviewed from the viewer's side, as shown in FIG. 14( b). In other words,the black frit 144 and the silver frit 146 frame the portion of thecoated glass substrate 140, with the black frit 144 being the “innermat” and the silver frit 146 being the “outer mat” when viewed from theplasma's side shown in FIG. 14( c). By comparison, the “single mat”visible from the viewer's side is the black frit 144. It will beappreciated that in some instances at least some black frit material maybe visible “outside” the silver frit 146, but its presence generally isnot a problem since the bezel or frame of the plasma display devicetypically conceals such areas, anyway.

In practice, the assembly shown in the FIG. 14 embodiment is made asfollows. A front cover glass 142 is provided. It is coated with blackfrit 144 and silver frit 146 and cut to a predetermined size appropriatefor the PDP in which it will be housed (e.g., such that the visible area140 has a 42″, 48″, 50″, 55″, or larger or smaller diagonal dimension).The front cover glass 142 may be cut and then coated with black frit 144and silver frit 146. The assembly including the front cover glass 142,black frit 144, and silver frit 146 is then fired and/or tempered. TheTCC 148 finally is applied to the cut, fired/tempered assembly,typically via sputter coating or the like. Ultimately, a visible area140 that is coated with TCC 148 will be framed by the black frit 144 andsilver frit 146. It is noted that in this technique, the TCC 148 isapplied over the black frit 144 and silver frit 146 such that, whenultimately assembled into a plasma display device, it will be theclosest layer to the plasma television portion of assembly.

In view of the description provided above, it will be appreciated thatthe TCC 148 is applied after any kind of heat treatment and after thesilver and black frits are applied. Furthermore, because the glasssubstrate 142 is cut to the appropriate predetermined size, it must becoated at this size. In other words, the TCC 148 is applied after theglass substrate 142 is cut to an appropriate size.

Although this process has been successful in producing high-quality PDPsand thus high-quality plasma display devices, further improvements arestill possible and desirable. For example, the process described aboveoften leads to a significant amount of waste and/or presents challengeswhen the TCC is applied. The assembly lines that provide the TCCcoatings (e.g., sputtering assembly lines) typically are configured toaccommodate stock, non-cut sheets that fit substantially the entire “bedsize” of a conveyor. Unfortunately, the above-described process requirescoating cut glass sheets. These cut glass sheets do not occupy the fulldimensions of a typical conveyor or bed size, which leads to at leastsome of the problems noted below and/or presents other challenges.

To increase the yield of the coating process, various cut glass sheetsmay be arranged on the conveyor in close relative proximity to oneanother in order to attempt to fill up the area on the conveyor. Inother words, cut glass sheets may be placed on a conveyor so as toapproximate a large, un-cut glass sheet that would otherwise occupysubstantially the entire bed size of the conveyor. Unfortunately, thiscompromise approach often takes time and/or significant manual effort,related at least in part to the careful arrangement of the cut glasssheets. Even with the attempted maximization of space, sputteredmaterial is often wasted. Additionally, because the sheets oftentimesare small compared to bulk non-cut sheets, some sizes cannot be coatedat all, while others inadvertently fall through rollers provided on theassembly line or are otherwise damaged or destroyed during the coatingprocess.

Thus, it will be appreciated that there is a need in the art forimproved PDPs, and/or improved PDP manufacturing techniques.

In certain example embodiments of this invention, a plasma display panel(PDP) includes a filter supported by a glass substrate forblocking/shielding substantial amounts of electromagnetic waves, withthe filter being supported by a side of the substrate opposite a viewer.A black frit and a silver frit comprise a filter frame and are supportedby the filter such that the filter is closer to the glass substrate thaneither or both of the frits. The filter has high visible transmission,and is capable of blocking/shielding electromagnetic waves. In certainexample embodiments, a silver based coating of the EMI filter reducesdamage from EMI radiation through highly conductive Ag layers, blockssignificant amounts of NIR and IR radiation from outdoor sunlight toreduce PDP panel temperature, and enhances contrast ratio throughreduced reflection, while maintaining high visible transmission. Incertain example embodiments, the filter is a TCC filter. Advantageously,a TCC may be coated on a stock, non-cut glass sheet.

In certain example embodiments, a plasma display device is provided. Aplasma display panel is provided. An electromagnetic interference (EMI)filter is provided at a front portion of the plasma display panel. TheEMI filter includes a multi-layer silver-inclusive transparentconductive coating (TCC) supported by an inner surface of a glasssubstrate. An inner black frit frame is disposed around a portion of theglass substrate that corresponds to a visible portion of the plasmadisplay panel. An outer silver frit frame is disposed around the innerblack frit frame at the periphery of the glass substrate. The TCC isprovided closer to the glass substrate than the inner and outer fritframes.

In certain example embodiments, a method of making a plasma displaydevice including a plasma display panel and an electromagneticinterference (EMI) filter provided at a front portion of the plasmadisplay panel is provided. A glass substrate is provided. A multi-layersilver-inclusive transparent conductive coating (TCC) is sputter coatedon an inner surface of the substrate. After the sputter-coating of theTCC, the substrate is cut to a predetermined. An inner black frit frameis applied around a portion of the glass substrate that corresponds to avisible portion of the plasma display panel. An outer silver frit frameis applied around the inner black frit frame such that the outer silverfrit frame will be located at the periphery of the cut glass substrate.At least one high-temperature treatment is performed. The at least onehigh-temperature treatment heat treats the cut substrate and meltstogether the black and silver frit frames. The TCC is provided closer tothe glass substrate than the inner and outer frit frames.

In certain example embodiments, a method of making an electromagneticinterference (EMI) filter for a plasma display device is provided. Aglass substrate is provided. A multi-layer silver-inclusive transparentconductive coating (TCC) is sputter coated on an inner surface of thesubstrate. After the sputter-coating of the TCC, the substrate is cut toa predetermined. An inner black frit frame is applied around a portionof the glass substrate that corresponds to a visible portion of theplasma display panel. An outer silver frit frame is applied around theinner black frit frame such that the outer silver frit frame will belocated at the periphery of the cut glass substrate. At least onehigh-temperature treatment is performed. The at least onehigh-temperature treatment heat treats the cut substrate and meltstogether the black and silver frit frames. The TCC is provided closer tothe glass substrate than the inner and outer frit frames.

In certain example embodiments, an electromagnetic interference (EMI)filter for use with a plasma display panel of a plasma display device isprovided. A multi-layer silver-inclusive transparent conductive coating(TCC) is supported by an inner surface of a glass substrate. An innerblack frit frame is disposed around a portion of the glass substratethat corresponds to a visible portion of the plasma display panel. Anouter silver frit frame is disposed around the inner black frit frame atthe periphery of the glass substrate. The TCC is provided closer to theglass substrate than the inner and outer frit frames.

In certain example embodiments, a method of making a plasma displaydevice including a plasma display panel and an electromagneticinterference (EMI) filter provided at a front portion of the plasmadisplay panel is provided. A glass substrate is provided. The glasssubstrate includes a sputter deposited multi-layer silver-inclusivetransparent conductive coating (TCC) on an inner surface thereof. Theglass substrate has been cut to a predetermined size following thesputter depositing of the TCC. An inner black frit frame is appliedaround a portion of the glass substrate that corresponds to a visibleportion of the plasma display panel. An outer silver frit frame isapplied around the inner black frit frame such that the outer silverfrit frame will be located at the periphery of the cut glass substrate.At least one high-temperature treatment is performed. The at least onehigh-temperature treatment heat treats the cut substrate and meltstogether the black and silver frit frames. The TCC is provided closer tothe glass substrate than the inner and outer frit frames. The innerblack frit frame is non-conductive and the outer silver frit frame isconductive.

In certain example embodiments, a plasma display device is provided. Aplasma display panel is provided. An electromagnetic interference (EMI)filter is provided at a front portion of the plasma display panel. TheEMI filter includes a multi-layer silver-inclusive transparentconductive coating (TCC) supported by an inner surface of a glasssubstrate. A conductive black frit frame is disposed around theperiphery of the glass substrate. The TCC is provided closer to theglass substrate than the conductive black frit frame.

In certain example embodiments, a method of making a plasma displaydevice including a plasma display panel and an electromagneticinterference (EMI) filter provided at a front portion of the plasmadisplay panel is provided. A glass substrate is provided. The glasssubstrate includes a sputter deposited multi-layer silver-inclusivetransparent conductive coating (TCC) on an inner surface thereof. Theglass substrate has been cut to a predetermined size following thesputter depositing of the TCC. A conductive black frit frame is appliedaround the periphery of the cut glass substrate. At least onehigh-temperature treatment is performed. The at least onehigh-temperature treatment heat treats the cut substrate and firing theconductive black frit frame. The TCC is provided closer to the glasssubstrate than the conductive black frit frames.

As noted above, when using a TCC, a conductive peripheral frame layer(frit) may be screen printed either on the bare glass substrate prior toTCC coating or on the coated glass substrate. Indeed, as shown in anddescribed in connection with FIG. 16 below, the conductive buss barmakes contact with the metal frame of the television (e.g., throughconductive tape, etc.). In certain current techniques used successfullyby the assignee of the instant invention, the conductive buss barcomprises either a silver frit or a layered combination of a conductivesilver frit and a non-conductive black frit (e.g., to produce a moreaesthetically pleasing product). Unfortunately, however, the screenprinting of the conductive frit on the glass adds process steps,increases manufacturing costs, and reduces manufacturing yield, e.g.,for the reason described above. Furthermore, although the use of aconductive black frit has been successfully implemented by the assigneeof the instant invention, further improvements are still possible.Indeed, it will be appreciated that the desire to reduce the cost ofcomponents in a plasma television is ongoing, and that one particulartarget for cost reduction involves yet further reductions in costsrelated to EMI filters.

In certain example embodiments of this invention, there is provided aplasma display device comprising a plasma display panel (PDP); and anelectromagnetic interference (EMI) filter provided at a front portion ofthe plasma display panel. The EMI filter includes an EMI coatingsupported by a glass substrate, with the EMI coating including thefollowing layers moving away from the glass substrate: a first highindex layer having a refractive index (n) of at least about 2.2; a firstlayer comprising silicon nitride; a first layer comprising zinc oxide; afirst EMI shielding layer comprising silver contacting the first layercomprising zinc oxide; a first layer comprising an oxide of Ni and/or Crcontacting the first EMI shielding layer comprising silver; a firstmetal oxide layer; a second layer of silicon nitride; a second layercomprising zinc oxide; a second EMI shielding layer comprising silvercontacting the second layer comprising zinc oxide; a second layercomprising an oxide of Ni and/or Cr contacting the second EMI shieldinglayer comprising silver; a second metal oxide layer; a third layer ofsilicon nitride; a third layer comprising zinc oxide; a third EMIshielding layer comprising silver contacting the third layer comprisingzinc oxide; a third layer comprising an oxide of Ni and/or Cr contactingthe third EMI shielding layer comprising silver; and an overcoat layercomprising a transparent conducting oxide (TCO). The EMI filter has asheet resistance of less than about 1 ohm.

In certain example embodiments of this invention, there is provided aplasma display device comprising a plasma display panel (PDP) and anelectromagnetic interference (EMI) filter provided in direct electriccontact with a front portion of the plasma display panel. The EMI filterincludes an EMI coating supported by a glass substrate, with the EMIcoating including the following layers moving away from the glasssubstrate: an anti-reflective coating; a first dielectric layer; a firstEMI shielding layer comprising silver; a second dielectric layer; asecond EMI shielding layer comprising silver; a third dielectric layer;a third EMI shielding layer comprising silver; a fourth dielectriclayer; a fourth EMI shielding layer comprising silver; and an overcoatlayer comprising a transparent conducting oxide (TCO). The glasssubstrate and the EMI coating combined have a visible transmission of atleast about 60%. The EMI filter has a sheet resistance of less thanabout 0.9 ohm. The TCO has a refractive index of about 1.95-2.05.

In certain example embodiments of this invention, there is provided anEMI filter for a plasma display device comprising an EMI coatingsupported by a glass substrate. The EMI coating includes the followinglayers moving away from the glass substrate: a first high refractiveindex layer; a first layer comprising silicon nitride; a first layercomprising zinc oxide; a first EMI shielding layer comprising silvercontacting the first layer comprising zinc oxide; a first layercomprising an oxide of Ni and/or Cr contacting the first EMI shieldinglayer comprising silver; a first metal oxide layer; a second layer ofsilicon nitride; a second layer comprising zinc oxide; a second EMIshielding layer comprising silver contacting the second layer comprisingzinc oxide; a second layer comprising an oxide of Ni and/or Crcontacting the second EMI shielding layer comprising silver; a secondmetal oxide layer; a third layer of silicon nitride; a third layercomprising zinc oxide; a third EMI shielding layer comprising silvercontacting the third layer comprising zinc oxide; a third layercomprising an oxide of Ni and/or Cr contacting the third EMI shieldinglayer comprising silver; a third metal oxide layer; a fourth layer ofsilicon nitride; a fourth layer comprising zinc oxide; a fourth EMIshielding layer comprising silver contacting the fourth layer comprisingzinc oxide; a fourth layer comprising an oxide of Ni and/or Crcontacting the fourth EMI shielding layer comprising silver; and anovercoat layer comprising a transparent conducting oxide (TCO). The EMIfilter has a sheet resistance of less than about 1 ohm. The overcoatlayer comprising the TCO is about 30-40 nm thick. The TCO has arefractive index of about 1.95-2.05, more preferably about 2.0.

The features, aspects, advantages, and example embodiments describedherein may be combined to realize yet further embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages may be better and morecompletely understood by reference to the following detailed descriptionof exemplary illustrative embodiments in conjunction with the drawings,of which:

FIG. 1( a) is a cross sectional view of an EMI filter for a plasmadisplay panel (e.g., PDP panel) according to an example embodiment ofthis invention.

FIG. 1( b) is a cross sectional view of a PDP panel including an EMIfilter (e.g., the filter of any embodiment herein) according to anexample embodiment of this invention.

FIG. 2 is a transmission/reflectance vs. wavelength graph illustratingoptical characteristics of the filter of FIG. 1( a) according to anexample embodiment of this invention.

FIG. 3 is a cross sectional view of an EMI filter for a display panel(e.g., PDP panel) according to another example embodiment of thisinvention.

FIG. 4 is a listing of the layers of an EMI filter for a display panel(e.g., PDP panel) according to another example embodiment of thisinvention.

FIG. 5 is a listing of the layers of an example antireflection (AR)coating which may optionally be used in conjunction with an EMI coatingin certain example embodiments of this invention.

FIG. 6 is a cross sectional view of the EMI filter (TCC) (of anyembodiment of this invention), front cover glass, and optional ARcoating for use at the front of a PDP panel according to an exampleembodiment of this invention.

FIG. 7 is a cross sectional view of the EMI filter (TCC) (of anyembodiment of this invention), front cover glass, and a pair of optionalAR coatings for use at the front of a PDP panel according to anotherexample embodiment of this invention.

FIG. 8 is a cross sectional view of the EMI filter (TCC) (of anyembodiment of this invention), front cover glass, and a pair of optionalAR coatings for use at the front of a PDP panel according to anotherexample embodiment of this invention.

FIG. 9 is a table listing example optical characteristics of filterstructures of certain example embodiments of this invention.

FIG. 10 is a transmission (T)/reflectance (R) vs. wavelength graphillustrating optical characteristics of the filters according to variousexample embodiments of this invention.

FIG. 11 is a graph illustrating normalized absorption spectrum ofexample optional pink dye which may be used in certain exampleembodiments of this invention.

FIG. 12 is a table listing example optical characteristics of filterstructures of certain example embodiments of this invention whichinclude the use of dye.

FIG. 13 is a transmission (T)/reflectance (R) vs. wavelength graphillustrating optical characteristics of the filters according to variousexample embodiments of this invention which include the use of dye.

FIG. 14( a) is a cross sectional view of the EMI filter, front coverglass, and black and silver frit frames for use at the front of a PDPpanel.

FIG. 14( b) is a front or viewer's view of the EMI filter and black fritframe for use at the front of a PDP panel.

FIG. 14( c) is a rear or plasma view of the EMI filter and black andsilver frit frames for use at the front of a PDP panel.

FIG. 15( a) is a cross sectional view of the EMI filter (TCC), frontcover glass, and black and silver frit frames for use at the front of aPDP panel according to an example embodiment.

FIG. 15( b) is a front or viewer's view of the EMI filter (TCC) andblack and silver frit frames for use at the front of a PDP panelaccording to an example embodiment.

FIG. 15( c) is a rear or plasma view of the EMI filter (TCC) and blackand silver frit frames for use at the front of a PDP panel according toan example embodiment.

FIG. 16 is a cross sectional view of an illustrative plasma displayassembly including a non-black frame that is substantially entirelyconcealed via a bezel according to an example embodiment.

FIG. 17 is a cross sectional view of an illustrative plasma displayassembly including concentric non-conductive black and conductive silverframes according to an example embodiment.

FIG. 18 shows percent reflectance in the visible spectrum for blackfrits through the glass usable in connection with certain exampleembodiments.

FIG. 19 is a cross sectional view of an illustrative plasma displayassembly including a low reflectance conductive black frame according toan example embodiment.

FIG. 20 is a cross sectional view of an EMI filter for a plasma displaypanel (e.g., PDP panel) according to an example embodiment of thisinvention.

FIG. 21 is a cross sectional view of an EMI filter for a plasma displaypanel (e.g., PDP panel) that does not necessarily require a conductivebus bar or conductive frame according to an example embodiment of thisinvention.

FIG. 22 is a cross sectional view of an EMI filter for a plasma displaypanel (e.g., PDP panel) that does not necessarily require a conductivebus bar or conductive frame according to an example embodiment of thisinvention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

Referring now more particularly to the accompanying drawings in whichlike reference numerals indicate like parts/layers throughout theseveral views.

In certain example embodiments, a black frit and a silver frit comprisea filter frame and are supported by the filter such that the filter iscloser to the glass substrate than either or both of the frits.Alternatively, in certain example embodiments, a conductive black fritcomprises a filter frame and is supported by the filter such that thefilter is closer to the glass substrate than the frit. Advantageously, atransparent conductive coating (TCC) may be coated on a stock, non-cutglass sheet, with the glass sheet later being cut to an appropriatesize. In certain example embodiments, the TCC may be multi-layered andinclude 2 or more layers of silver.

For example, a TCC usable with certain example embodiments of thisinvention may be an Ag-based multiple layered TCC for displayapplications (e.g., PDP applications). This EMI filter coating includesthree or more Ag based layers sandwiched between metal oxides, nitrides,or oxynitrides. It provides the functions of blocking EMI radiation andminimizing/reducing near infrared and infrared transmissions. The Agbased transparent conductive coating can be manufactured by magnetronsputtering on glass in certain example embodiments. The coating on glassmay go through a post heat-treatment in a typical oven or temperingfurnace to enhance glass strength and increase coating conductivity andtransparency in certain example embodiments (e.g., heat treatment). Incertain example embodiments, the Ag-based TCC (or EMI filter) coatingincludes or consists of four layers of ZnOx/Ag/NiCrOx sandwiched betweenmetal oxides and nitrides. In certain example embodiments, the metaloxides (e.g., tin oxide, zinc oxide) and nitrides (e.g., siliconnitride) used have refractive indices (n) in visible higher than 1.8,and can be nonconductive such as SiNx or conductive such as ZnAlOx. Incertain example embodiments, certain of the materials (e.g., Ag, zincoxide based layers, and NiCrOx based layers) are the same for all threeor four stacks, but the thickness of the dielectric and Ag layers areadjusted to meet the sheet resistance and optics targets for each of thelayer stacks. Moreover, other layers may differ from stack to stack inorder to enhance durability and optical performance. In certain exampleembodiments, the EMI filter may also include a conductive frit framearound the periphery to provide a low conductance contact to the housingof the plasma TV. The completed filter may also include AR coating filmlaminated to the front surface to reduce display reflectance and alaminate with a purple and/or pink dye attached to the back of thecoated glass to improve color performance of the plasma TV. Furtherdetails of such an example EMI filter are provided below. It will beappreciated that other EMI filters may be used in connection withexample embodiments of this invention.

FIGS. 15( a)-15(c) provide an example view of how a PDP filter may bearranged with reference to a front cover glass according to an exampleembodiment. More particularly, FIG. 15( a) is a cross sectional view ofthe EMI filter (TCC), front cover glass, and black and silver fritframes for use at the front of a PDP panel according to an exampleembodiment, FIG. 15( b) is a front or viewer's view of the EMI filter(TCC) and black and silver frit frames for use at the front of a PDPpanel according to an example embodiment, and FIG. 15( c) is a rear orplasma view of the EMI filter (TCC) and black and silver frit frames foruse at the front of a PDP panel according to an example embodiment.

Similar to the arrangement shown in FIG. 14( a), the arrangement shownin FIG. 15( a) includes a TCC coating 148 located on a side of the frontcover glass 142 opposite the viewer. However, unlike the FIG. 14( a)arrangement, the TCC 148 of the FIG. 15( a) arrangement is providedadjacent to the glass substrate 142. The black frit 144 and silver frit146 are supported by the TCC 148, such that they are farther from theviewer than the TCC 148.

As shown in FIGS. 15( b) and 15(c), the black frit 144 and silver frit146 form frames around the visible area 150. Also as shown, the blackfrit 144 may be applied around the visible area 150, although it neednot extend all the way to the edge of the glass. By contrast, the silverfrit 146 is provided outside or around the black frit at the peripheryof the front cover glass 142. Thus, in certain example embodiments, thesilver frit 146 may run up to the edge of the front cover glass 142 andmay extend around its periphery. The silver frit 146 and the black frit144 may overlap slightly, but the silver frit 146 should not extend intothe viewing area 150. As such, the black frit 144 forms an inner frame,whereas the silver frit 146 forms an outer frame although, as notedabove, the silver frit 146 and the black frit 144 may sometimes overlapslightly. Indeed, it is sometimes hard to apply frit material withprecision and it is therefore sometimes hard to create exact boundaries.However, the silver frit 146 may be applied in a wide manner and cancover some of the black frit 144, provided that the silver frit is notpresent or at is at least not perceivable in the visible area 150.

The PDP of certain example embodiments may be made according to severaldifferent processes. A glass substrate to be coated is provided. The TCCis applied to a surface of the glass substrate that faces away from theviewer, i.e., towards the plasma television. The TCC may be applied viasputter coating or the like. The TCC sometimes may not be activateduntil the coated substrate is heat treated, e.g., using the conditionsprovided above. The now-coated glass substrate may be cut to size, andthen the black and silver frits may be applied after the TCC is applied.Alternatively, the black and silver frits may be applied to thenow-coated glass substrate, and it may then be cut to size.

The heat treatment may take place before or after the black and silverfrits are applied. If the heat treatment takes place before the blackand silver frits are applied, the black and silver frits may be firedtogether at a high temperature in another step so that they are melted.However, this high-temperature firing may be accomplished together withthe tempering and/or the activation of the TCC. Accordingly, the blackand silver frits may be melted and the heat treatment may take placeafter the cutting. Accordingly, it will be appreciated that certainexample embodiments may enable a single heat treatment step to be usedto activate the TCC and also melt the black and silver frits.

The black frit generally is non-conductive, whereas the silver fritgenerally is conductive. The black frit commonly used to form frames invehicle front windshield applications may be used in connection withcertain example embodiments, and/or the silver frit commonly used invehicle backlite defogging applications may be used in connection withcertain example embodiments. For example, the black frit used in certainexample embodiments may be commercially available from Johnson Mattheyunder the trade name 2L52M400/IR738A, or may be commercially availablefrom Ferro under the trade name 24-8844 Black in 1639. Also, forexample, the silver frit used in certain example embodiments may becommercially available from BASF under the trade name Silver AP Inks.

Certain conventional EMI filters for plasma displays may utilize a Cumesh and/or a Transparent Conductive Coating (TCC) for EMI blocking. Inany configuration, it is advantageous to have a low resistance ohmiccontact between the EMI blocking layer and the grounded metal frame towhich the filter is attached. As noted above, the prior art approach forusing a TCC EMI blocking layer involves screen printing a blackperipheral frame layer along with a silver frit frame on a bare glasssubstrate cut to final filter size. This printing process is followed bythe coating of the TCC, e.g. by magnetron sputtering or the like. Thus,in this filter structure, the frame layers are positioned between theglass and the EMI coating. As explained above, this approach is notcost-effective, as it involves coating small glass substrates.

In contrast to these prior art approaches, certain example embodimentsof this invention relate to a filter structure that reduce cost byimplementing a more cost-effective technique. That is, in certainexample embodiments, the TCC is coated on large size glass substrates(e.g., on large stock sheets that typically are up to about 3.21 m×6 msheets), the coated glass is subsequently cut to final filter size, andthe conductive frame is screen printed on top of the TCC. Thus, the EMIcoating is positioned between the glass and the frame layer(s) in thefilter structure of certain example embodiments, unlike those ofconventional TCC-based EMI filters.

For some filter applications, the conductive frame does not need to beblack. For instance, this may be the case when the frame issubstantially entirely hidden behind the display bezel, as shown, forexample, in FIG. 16. In the example embodiment shown in FIG. 16, forexample, a conventional silver frit or conductive paste may be used suchas, for example, BASF BF-8366 A6174LE. In greater detail, FIG. 16 is across sectional view of an illustrative plasma display assemblyincluding a non-black frame that is substantially entirely concealed viaa bezel 164 according to an example embodiment. In FIG. 16, a TCC EMIfilter 148 is provided on the glass substrate 142, and a PDP panel isprovided on the TCC EMI filter 148 opposite the glass substrate 142. Aconductive silver frit frame 146 is provided on the TCC EMI filter 148,and a grounded metal frame 148 is in contact with the conductive silverfrit frame 146. As alluded to above, the bezel 164 substantiallyentirely conceals the conductive silver frit frame 146 and the groundedmetal frame 148.

As noted above, in conventional prior art filters having a TCC, a black,non-conductive frame is printed first followed by a conductive silverfrit. The TCC is deposited on top of the frame layer and makes goodelectrical contact with the silver frit. However, in some cases wherethe TCC is deposited first followed by the non-conductive black frameand the silver frit frame, there is no longer a low resistance contactbetween the TCC and the conductive silver frit. This may be unacceptablein some applications and also sometimes may lead to poor EMI blocking ofthe filter. Indeed, it would be desirable to lower sheet resistance tobelow about 0.2 Ω/square, more desirable to lower sheet resistance tolower than about 0.15 Ω/square, and still more desirable to lower sheetresistance to below about 0.01 Ω/square, as measured, for example, by afour-point probe directly or indirectly on the fired frit.

To reduce this problem while also providing low sheet resistances,certain example embodiments provide the arrangement shown in FIG. 17,which is a cross sectional view of an illustrative plasma displayassembly including concentric non-conductive black 144 and conductivesilver frames 146 according to an example embodiment. The conductivesilver frit frame 146 is located at the periphery of the glass substrateon the TCC EMI filter 148. In certain example embodiments, theconductive silver frit frame 146 may be spaced apart from the blackframe 144, thus forming a gap between the silver frit frame 146 and theblack frame 144 such that the silver frit frame 146 is substantially notvisible to the viewer whereas the black frame 144 may or may not be atleast partially visible to the viewer. In certain example embodiments,the black frame 144 may be provided on the TCC EMI first so that whenthe silver frit frame 146 is applied, any excess is applied over theblack frame 144, thereby substantially concealing it from the viewer. Incertain example embodiments, the silver frit frame 146 may be providedon the glass substrate 142 prior to the black frame 144 being applied,provided that the silver frit frame 146 is substantially entirely hiddenfrom the viewer.

It is sometimes not feasible or desirable to provide a large bezel.Thus, it is sometimes desirable to use an alternative arrangement thatreduces the size of the bezel, e.g., by concealing the conductive silverfrit frame 146 in different way. Accordingly, it will be appreciatedthat the example embodiment shown in FIG. 17 can accommodate smallerbezels, as the black frame 144 may help to conceal the silver frit frame146. Additionally, the example embodiment shown in FIG. 17 preferablyachieves a sheet resistance of less than about 0.2 Ω/square, morepreferably less than about 0.15 Ω/square, and more preferably less thanabout 0.01 Ω/square, as measured, for example, by a standard four-pointprobe directly or indirectly on the fired frit. It is believed that thepresence of the silver keeps the sheet resistance low and sometimes evennegligible. Furthermore, it is believed that any other conductivematerial would cause an increased sheet resistance.

Non-conductive black frames considered to be acceptable for lowreflection black coatings include, for example, Johnson-Matthey2T55M050-IR601 and Ferro 24-8337-1537. Additionally, there are manynon-conductive black enamels that may be used for this purpose. Anexample of the conductive layer is BASF BF-8366 A6174LE. Additionally,there are many silver inks available for this purpose. FIG. 18 showspercent reflectance in the visible spectrum for black frits usable inconnection with certain example embodiments. That is, FIG. 18 plots thereflectance of several black frits through the glass on the TCC afterfiring at 600 degrees C. The percent reflectance of the black fritsthrough the glass of certain example embodiments in the visible spectrum(e.g., about 400-700 nm) at 8 and 45 degree angles off of the glasssubstrate preferably is less than about 10%, more preferably less thanabout 8%, and still more preferably less than about 7%. It will beappreciated that the percent reflectance may be slightly higher whentaken at an angle of 8 degrees off of the glass in comparison to whentaken at an angle of 45 degrees off of the glass.

In certain example embodiments, the black frit may be applied before thesilver frit. In certain example embodiments, the silver frit may beapplied before the black frit, e.g., when the silver frit is concealedby the bezel of the plasma display device and/or otherwise substantiallynot visible to a viewer thereof.

The example embodiments described above have included separate silverand black frits. However, to further reduce cost of the filter, thefunctionality of the separate black and conductive frames may becombined into a single material. Such a material may be a conductiveblack frame layer, as shown, for example, in FIG. 19. In other words,FIG. 19 is a cross sectional view of an illustrative plasma displayassembly including a low reflectance conductive black frame according toan example embodiment. As shown in FIG. 19, a glass substrate 142 has aTCC EMI filter 148 provided thereon. A low reflectance conductive blackframe 192 is provided on the TCC EMI filter opposite the glasssubstrate. The low reflectance conductive black frame 192 of FIG. 19replaces both the conductive silver frit frame and the black frame, asit is both conductive and aesthetically more acceptable than typicalsilver frit frames. Materials for black conductive frames are known andinclude, for example, that which is disclosed in co-pending and commonlyassigned U.S. application Ser. No. 10/956,371. Of course, it will beappreciated that any conductive black material may be used in connectionwith certain example embodiments. For example, a suitable material maybe a mixture comprising about 60% silver, with black constituting themajority of the remainder of the mixture and with other materials suchas pigment modifiers, rheology modifiers, oxidation modifiers, and glassfrit also forming a part of the mixture. It will be appreciated thatmore or less silver can be used, for example, in the range of about50-70% silver, although the conductivity of the material is expected todrop-off below a certain threshold percentage of silver. The conductiveblack frit of certain example embodiments may be able to withstandtemperatures used to conduct heat treatments (e.g., temperatures up toabout 650 degrees C.). In general, conductive black frits according tocertain example embodiments may be selected and/or mixed and optimizedso as to have some or all of the properties that separate silver andblack frits would have. Thus, for example, conductive black fritsaccording to certain example embodiments may be selected and/or mixedand optimized to have the conductivity of or approaching that of aconventional silver frit and the black color of a conventional blackfrit, while also having a low reflectance when viewed through the glass.

The example embodiment shown in FIG. 19 preferably achieves a sheetresistance of less than about 0.2 Ω/square, more preferably less thanabout 0.15 Ω/square, and still more preferably less than about 0.01Ω/square, as measured, for example, by a four-point probe directly orindirectly on the fired frit. As above, it is believed that the presenceof the silver keeps the sheet resistance low and sometimes evennegligible, and it is believed that any other conductive material wouldcause an increased sheet resistance. The conductive black material maybe applied to various thicknesses. For example, the conductive blackmaterial may be applied to a thickness of about 20-60 μm, morepreferably about 25-45 μm, and still more preferably about 30 μm.

The conductive black material and the TCC may be optimized with respectto each other, e.g., to obtain a low reflectance from the viewer side.For example, the percent reflectance of the conductive black framesthrough the glass of certain example embodiments in the visible spectrum(e.g., about 400-700 nm) at 8 and 45 degree angles off of the glasssubstrate preferably is less than about 10%, more preferably less thanabout 8%, and still more preferably less than about 7%. Again, it willbe appreciated that the percent reflectance may be slightly higher whentaken at an angle of 8 degrees off of the glass in comparison to whentaken at an angle of 45 degrees off of the glass.

It will be appreciated that when viewed by a viewer through the TCC, theconductive black frame may not appear “black,” sometimes resulting in aless aesthetically appealing color and/or other appearance of the framefrom the viewer's perspective. This is related to the TCC's effect onthe viewer's perception of the conductive black frame. Accordingly, theblack conductive material and the TCC may be further optimized withrespect to each other so that, when viewed by a viewer through the TCC,the conductive black frame actually appears to be “black” or at least“blacker.” This may be accomplished in certain example embodiments byintroducing pigment additives or coloring agents to the black materialso that the black material looks “black” or at least “blacker” whenviewed by a viewer through the TCC. In other words, the introduction ofpigment additives or coloring agents to the black material may reduceperceived discoloration effects when the viewer views the conductiveblack material through the TCC.

The techniques described herein may be advantageous for a number ofreasons. For example, a TCC may be coated on stock non-cut sheets, whichoften are the size of large sliding glass doors. In other words, thetechniques of certain example embodiments reduce or eliminate the needto cut glass sheets to a desired size prior to applying an EMI filterthereon. This, in turn, reduces the amount of wasted product (e.g.,reduces the amount of wasted glass and/or wasted sputtering material)and/or time (e.g., since products do not need to be carefully arrangedto increase the area covered by glass to be coated on a conveyor), as alarger initial sheet may take advantage of substantially the entire bedsize of a standard conveyor used for providing sputtered coatings.Additionally, large stock glass sheets tend not to fall between rollersand thus reduce the amount of breakage and/or damaging associated withsmaller sheets that coated using other processes.

Certain example embodiments are also advantageous in that only one heattreatment needed. In other words, certain example embodiments enable aglass substrate to be heat treated, a coating to be activated, and fritsto be melted in a single high temperature step.

A description of the EMI filter alluded to above will now be provided.FIG. 1( a) is a cross sectional view of an EMI filter for use in a PDPpanel (or other type of display panel) according to an exampleembodiment of this invention. FIG. 1( b) is a cross sectional viewillustrating the filter of FIG. 1( a) on a PDP panel. As shown in FIG.1( b), the filter of FIG. 1( a) is provided on the interior side (sidefacing away from the sun) of a front cover glass substrate at the frontof the PDP. The EMI filters according to example embodiments of thisinvention may or may not be used in conjunctions with antireflection(AR) coatings. An AR coating may be provided on the cover glass, on theopposite or the same side as the EMI filter coating. The PDP panel 40shown in FIG. 1( b) may be any suitable type of PDP panel. Example PDPpanels are described in US 2006/0083938 (e.g., see FIG. 6), the entiretyof which is incorporated herein by reference. For purposes of example,the FIG. 1( a) filter structure may be used in place of 100 or 100′ inthe PDP device of FIG. 6 of US 2006/0083938, as an example applicationof this invention.

The EMI filter structure of FIG. 1 includes cover glass substrate 1(e.g., clear, green, bronze, or blue-green glass substrate from about1.0 to 10.0 mm thick, more preferably from about 1.0 mm to 3.5 mmthick), and EMI filter coating (or layer system) 30 provided on thesubstrate 1 either directly or indirectly. The coating (or layer system)30 includes: dielectric silicon nitride base layer 3 which may be Si₃N₄,of the Si-rich type for haze reduction, or of any other suitablestoichiometry in different embodiments of this invention, high indextitanium oxide inclusive layer 4, first lower contact layer 7 (whichcontacts conductive EMI shielding layer 9), first conductive andpreferably metallic EMI shielding layer 9, first upper contact layer 11(which contacts layer 9), dielectric or conductive metal oxide layer 13(which may be deposited in one or multiple steps in differentembodiments of this invention), second lower contact layer 17 (whichcontacts EMI shielding layer 19), second conductive and preferablymetallic EMI shielding layer 19, second upper contact layer 21 (whichcontacts layer 19), dielectric or conductive metal oxide layer 23,dielectric silicon nitride based layer(s) 25, 26 which may be Si₃N₄, ofthe Si-rich type for haze reduction, or of any other suitablestoichiometry in different embodiments of this invention, second highindex titanium oxide inclusive layer 24, third lower contact layer 27(which contacts conductive EMI shielding layer 29), third conductive andpreferably metallic EMI shielding layer 29, third upper contact layer 31(which contacts layer 29), dielectric or conductive metal oxide layer 33(which may be deposited in one or multiple steps in differentembodiments of this invention), fourth lower contact layer 37 (whichcontacts EMI shielding layer 39), fourth conductive and preferablymetallic EMI shielding layer 39, fourth upper contact layer 41 (whichcontacts layer 39), dielectric or conductive metal oxide layer 43, andprotective overcoat layer 45 of or including silicon nitride or thelike. The “contact” layers 7, 11, 17,21, 27, 31, 37 and 41 each contactat least one EMI shielding/reflecting layer (e.g., layer based on Ag)(9, 19, 29, 39). The aforesaid layers 3-45 make up the EMI shieldingcoating 30 which is provided on substrate I for blocking substantialamounts of EMI from being emitted from the PDP device. Example sheetresistances are 0.8, 1.2 and 1.6 ohm/sq. for the coatings 30 indifferent example embodiments. In certain example embodiments, thecoating 30 may have a sheet resistance of from about 0.5 to 1.8 ohms/sq.

An alternative (not shown) to the FIG. 1 embodiment involves splittingeach of metal oxide layers 13 and 33 into two different layers andprovided a silicon nitride based layer in between the split layers. Inother words, for example, tin oxide based layer 13 would be replacedwith a first tin oxide based layer 13′, a silicon nitride layer 13″ anda second tin oxide based layer 13′″. Likewise, tin oxide based layer 33would be replaced with a first tin oxide based layer 33′, a siliconnitride layer 33″ and a second tin oxide based layer 33′″. Thisalternative layer stack is particularly advantageous with respect toheat treated and heat treatable filters that may be used when, forexample, bus bar/black frit is applied on top of the coating 30. In suchembodiments, the use of the NiCrOx material for layers 11, 21, 31 and 41is advantageous in that it is more durable and provides for betterthermal stability compared to other possible materials such as zincoxide or zinc aluminum oxide.

Dielectric layers 3, 25, 26 and 45 preferably have a refractive index(n) of from about 1.9 to 2.1, more preferably from about 1.97 to 2.08,and may be of or include silicon nitride in certain embodiments of thisinvention. Silicon nitride layers 3, 25, 26 and 45 may, among otherthings, improve heat-treatability of the coated articles, e.g., such asthermal tempering or the like. The silicon nitride of one, two or all ofthese layers may be of the stoichiometric type (Si₃N₄) type, oralternatively of the Si-rich type in different embodiments of thisinvention. For example, Si-rich silicon nitride 3, 26 combined with zincoxide inclusive layer 7 (and/or 27) under a silver based EMI shieldinglayer 9 (and/or 29) may permit the silver to be deposited (e.g., viasputtering or the like) in a manner which causes its sheet resistance tobe lessened compared to if certain other material(s) were under thesilver (and thus, EMI shielding to be improved). Moreover, the presenceof free Si in a Si-rich silicon nitride inclusive layer 3 may allowcertain atoms such as sodium (Na) which migrate outwardly from the glass1 during HT to be more efficiently stopped by the Si-rich siliconnitride inclusive layer before they can reach the silver and damage thesame. Thus, it is believed that the oxidation caused by heat treatmentallows visible transmission to increase, and that the Si-richSi_(x)N_(y) can reduce the amount of damage done to the silver layer(s)during HT in certain example embodiments of this invention therebyallowing sheet resistance (R_(s)) to decrease in a satisfactory mannerand EMI shielding to be improved. In certain example embodiments, whenSi-rich silicon nitride us used in layer(s) 3 and/or 25, 26, the Si-richsilicon nitride layer as deposited may be characterized by Si_(x)N_(y)layer(s), where x/y may be from 0.76 to 1.5, more preferably from 0.8 to1.4, still more preferably from 0.85 to 1.2. Moreover, in certainexample embodiments, before and/or after HT the Si-rich Si_(x)N_(y)layer(s) may have an index of refraction “n” of at least 2.05, morepreferably of at least 2.07, and sometimes at least 2.10 (e.g., 632 nm)(note: stoichiometric Si₃N₄ which may also be used has an index “n” of2.02-2.04). In certain example embodiments, it has surprisingly beenfound that improved thermal stability is especially realizable when theSi-rich Si_(x)N_(y) layer(s) as deposited has an index of refraction “n”of at least 2.10, more preferably of at least 2.2, and most preferablyfrom 2.2 to 2.4. Also, the Si-rich Si_(x)N_(y) layer in certain exampleembodiments may have an extinction coefficient “k” of at least 0.001,more preferably of at least 0.003 (note: stoichiometric Si₃N₄ has anextinction coefficient “k” of effectively 0). Again, in certain exampleembodiments, it has surprisingly been found that improved thermalstability can be realized when “k” for the Si-rich Si_(x)N_(y) layer isfrom 0.001 to 0.05 as deposited (550 nm). It is noted that n and k tendto drop due to heat treatment. Any and/or all of the silicon nitridelayers (3, 25, 26, 45) discussed herein may be doped with othermaterials such as stainless steel or aluminum in certain exampleembodiments of this invention. For example, any and/or all siliconnitride layers discussed herein may optionally include from about 0-15%aluminum, more preferably from about 1 to 10% aluminum, most preferablyfrom 1-4% aluminum, in certain example embodiments of this invention.The silicon nitride may be deposited by sputtering a target of Si orSiAl in certain embodiments of this invention. These layers are providedin order to improve the reflection of EMI without sacrificing visibletransmission.

High index layers 4 and 24 are preferably of or including an oxide oftitanium (e.g., TiO₂, or other suitable stoichiometry) in certainexample embodiments of this invention. Layers 4 and 24 preferably have arefractive index (n) of at least about 2.2, more preferably of at leastabout 2.3, 2.4 or 2.45, in certain example embodiments of thisinvention. These layers 4 and 24 may be conductive or dielectric indifferent example embodiments of this invention. These layers areprovided in order to improve the reflection of EMI without sacrificingvisible transmission.

EMI shielding/reflecting layers 9, 19, 29 and 39 are preferablysubstantially or entirely metallic and/or conductive, and may compriseor consist essentially of silver (Ag), gold, or any other suitable EMIreflecting material. EMI shielding layers 9, 19, 29 and 39 help allowthe coating to have good conductivity and block EMI from being emittedfrom the PDP panel. It is possible for these layers to be slightlyoxidized in certain embodiments of this invention.

The upper contact layers 11, 21, 31 and 41 may be of or include nickel(Ni) oxide, chromium/chrome (Cr) oxide, or a nickel alloy oxide such asnickel chrome oxide (NiCrO_(x)), or other suitable material(s), incertain example embodiments of this invention. The use of, for example,NiCrO_(x) in these layers allows durability to be improved. TheNiCrO_(x) of layers 11 and/or 21 may be fully oxidized in certainembodiments of this invention (i.e., fully stoichiometric), oralternatively may only be partially oxidized. In certain instances, theNiCrO_(x) layers may be at least about 50% oxidized. These layers (e.g.,of or including an oxide of Ni and/or Cr) may or may not be oxidationgraded in different embodiments of this invention. Oxidation gradingmeans that the degree of oxidation in the layer changes throughout thethickness of the layer so that for example a contact layer may be gradedso as to be less oxidized at the contact interface with the immediatelyadjacent IR reflecting layer than at a portion of the contact layer(s)further or more/most distant from the immediately adjacent IR reflectinglayer, and these contact layers may or may not be continuous indifferent embodiments of this invention across the entire IR reflectinglayer. The use of the NiCrOx material for one, two, three or all oflayers 11, 21, 31 and 41 is advantageous in that it is more durable andprovides for better thermal stability compared to other possiblematerials such as zinc oxide or zinc aluminum oxide. This is especiallythe case with respect to heat treated and heat treatable filters thatmay be used when, for example, bus bariblack frit is applied on top ofthe coating 30 in certain applications.

Metal oxide layers 13, 23, 33 and 43 may be of or include tin oxide incertain example embodiments of this invention. These layers preferablyhave a refractive index (n) of from about 1.9 to 2.1 in certain exampleembodiments of this invention, more preferably from about 1.95 to 2.05.These layers may be doped with other material such as zinc in certaininstances. However, as with other layers herein, other materials may beused in different instances. These layers are provided in order toimprove the reflection of EMI without sacrificing visible transmission.

Lower contact layers 7, 17, 27 and 37 in certain embodiments of thisinvention are of or include zinc oxide (e.g., ZnO). The zinc oxide ofthese layers may contain other materials as well such as Al (e.g., toform ZnAlO_(x)). For example, in certain example embodiments of thisinvention, one or more of these zinc oxide layers may be doped with fromabout 1 to 10% Al, more preferably from about 1 to 5% Al, and mostpreferably about 2 to 4% Al. The use of zinc oxide under the silver 9,19, 29, 39 allows for an excellent quality of silver to be achievedthereby improving conductivity and improving EMI shielding.

Other layer(s) below or above the illustrated coating may also beprovided. Thus, while the layer system or coating is “on” or “supportedby” substrate 1 (directly or indirectly), other layer(s) may be providedtherebetween. Thus, for example, the coating of FIG. 1 may be considered“on” and “supported by” the substrate I even if other layer(s) areprovided between layer 3 and substrate 1. Moreover, certain layers ofthe illustrated coating may be removed in certain embodiments, whileothers may be added between the various layers or the various layer(s)may be split with other layer(s) added between the split sections inother embodiments of this invention without departing from the overallspirit of certain embodiments of this invention.

In certain example embodiments of this invention, the Ag-based EMIshielding layers in the coating have different thicknesses. This is bydesign, and is particularly advantageous. The different thicknesses ofthe silver based layers 9, 19, 29, 39 are optimized to obtain a lowvisible reflection as seen from outside of the PDP apparatus (i.e., fromthe glass side of the film, in most embodiments, namely when the coating30 is on the interior surface of the substrate 1 facing the plasma), andat the same time permitting high visible transmittance. Silver layersburied deeper in the stack (i.e., further from the plasma) are masked toa certain extent by the absorption in the preceeding layers; therefore,they can be made thicker to improve EMI shielding without adverselyaffecting outside reflectance to any significant extent. Thus, thethickness (physical thickness) of a silver based EMI shielding layer(s)(e.g., 39) further from the plasma of the PDP panel can be significantlythicker than the thickness of a silver based EMI shielding layer(s)(e.g., 9) closer to the plasma of the PDP panel. The total silverthickness is unevenly distributed across the coating 30 in order to takeadvantageous of this effect. The total thickness of all silver basedlayers (9, 19, 29, 39) combined may be from about 25-80 nm in certainexample embodiments of this invention, more preferably from about 30-70nm, whereas the total thickness of the entire coating 30 may be fromabout 300 to 400 nm, more preferably from about 325 to 380 nm, and mostpreferably from about 330 to 375 in certain example embodiments of thisinvention. In certain example embodiments, the thickness (physicalthickness) of a silver based EMI shielding layer(s) (e.g., 39 or 29)further from the plasma of the PDP panel is at least about 1 nm thicker(more preferably at least about 2 nm thicker, and possibly at leastabout 3 or 4 nm thicker) than the thickness of a silver based EMIshielding layer(s) (e.g., 9) closer to the plasma of the PDP panel.

FIG. 2 is a transmission/reflectance vs. wavelength graph illustratingoptical characteristics of the filter of FIG. 1( a) when designed for asheet resistance of 0.8 ohms/square, thereby having thick silverlayer(s). In FIG. 2, T stands for transmission, G stands for glass sidereflectance, and F stands for film side reflectance. It can be seen inFIG. 2 that film side (i.e., the side closest to the plasma) reflectanceof EMI such as NIR is enhanced (much reflectance) while visibletransmission (e.g., from 450-650 nm) is kept high. This provides for afilter having good/high visible transmission, but muchreflectance/absorption in the NIR region where undesirable wavelengthsare present. In certain example embodiments, the combination of thecoating 30 and the substrate 1 have a visible transmission of at leastabout 50%, more preferably of at least about 55%, 58% or 60% in certainexample embodiments of this invention.

FIG. 3 is a cross sectional view of an EMI filter for a display panel(e.g., PDP panel) according to another example embodiment of thisinvention. The FIG. 3 embodiment is the same as the FIG. 1( a)-(b)embodiment discussed above, except that certain thicknesses aredifferent because the FIG. 3 filter is designed for a higher sheetresistance (Rs of 1.64 ohms/square).

While various thicknesses and materials may be used in layers indifferent embodiments of this invention, example thicknesses andmaterials for the respective layers on the glass substrate 1 in the FIG.1-3 embodiments are as follows, from the glass substrate outwardly:

Example Materials/Thicknesses; FIG. 1-3 Embodiment Layer Preferred RangeMore Preferred Example Glass (1-10 mm thick) (nm) (nm) (nm) Si_(x)N_(y)(layer 3) 4-30 8-15 10-14 TiO_(x) (layer 4) 4-35 8-20 15 ZnO_(x) (layer7) 4-22 5-15 10 Ag (layer 9) 4-20 6-15  8-13 NiCrO_(x) (layer 11)0.3-4   0.5-2    1 SnO₂ (layer 13) 10-100 25-90  55-80 ZnO_(x) (layer17) 4-22 5-15 10 Ag (layer 19) 4-24 6-20  8-18 NiCrO_(x) (layer 21)0.3-4   0.5-2    1 SnO₂ (layer 23) 4-25 6-20 10-14 Si₃N₄ (layer 25)10-50  12-40  15-25 Si_(x)N_(y) (layer 26) 4-30 8-15 10-14 TiO_(x)(layer 24) 4-35 8-20 15 ZnO_(x) (layer 27) 4-22 5-15 10 Ag (layer 29)8-30 10-24  12-22 NiCrO_(x) (layer 31) 0.3-4   0.5-2    1 SnO₂ (layer33) 10-100 25-90  55-80 ZnO_(x) (layer 37) 4-22 5-15 10 Ag (layer 39)8-30 10-24  11-20 NiCrO_(x) (layer 41) 0.3-4   0.5-2    1 SnO₂ (layer43) 4-25 6-20 10-18 Si₃N₄ (layer 45) 10-50  15-40  18-32

In another example embodiment of this invention, FIG. 4 describes an Agbased TCC coating for use as an EMI filter in PDP applications of thelike as discussed above, the FIG. 4 coating 30 including four layerstacks of ZnOx/Ag/NiCrOx sandwiched between metal oxides and nitrides.The FIG. 4 coating has different thicknesses than the coating of FIGS.1-3, and also in FIG. 4 the layers 3, 25, 26, 24, 43 from the FIG. 1-3embodiments have been removed. This shows that all layers in the FIG. 1embodiment are not essential, and some may be removed in certaininstances. This FIG. 4 coating 30 may have a sheet resistance less than1.5 ohm/sq and 1.0 ohm/sq measured as coated and after heat-treatment,respectively, in certain example embodiments, and a neutral transmissionin visible higher than 55% or 60% in certain example embodiments. Thesheet resistance can be further reduced through the trade-off oftransmission in visible by increased Ag thickness. If a lowertransmission is desired, the transmission can be reduced by increasedNiCrOx thickness and/or reduced x value. Metal oxides and nitridesshould have optical index in visible higher than 1.8, and can benonconductive such as SiNx or conductive such as ZnAlOx in differentexample embodiments. A multiple layer structure can also be used toreplace each metal oxide, nitride, or oxynitride, such as replacing TiOxby SiNx/TiOx or SnOx by SnOx/SiNx/ZnOx.

Referring to FIG. 5, a broad band visible antireflection (AR) coating50, such as the one described in FIG. 5 or any other suitable ARcoating, can be applied on the opposite surface of the substrate 1 (seeFIGS. 6-8) and/or laminated atop of the TCC 30 (see FIGS. 7-8) tofurther enhance the optical performance of the Ag based EMI protectioncoating 30 in certain example embodiments of this invention. Examples ofusing this Ag based TCC coating for display applications are shown inFIGS. 6-8. As explained above, the various FIG. 6-8 filter structuresmay be used in place of 100 or 100′ in the PDP device of FIG. 6 of US2006/0083938, in example applications of this invention. Note that inFIGS. 6-8, optional additional substrate(s) 1′, 1″ may be glass orplastic, and the glue may be any suitable adhesive or the like. Forexample, in one example, a TCC coating 30 having 4 layers of Ag (asshown in FIGS. 1( a), 3 and 4) is used as part of cover glass 1structure for outdoor display applications, and FIGS. 6-8 illustrateexample designs of this cover glass structure with the optionalpossibility of using it together with an AR coating 50. Opticalperformance of example is summarized in FIG. 9 when TCC 30 (e.g., seeFIG. 4, or FIG. 1) and AR (e.g., see FIG. 5) are coated on oppositesurfaces of the substrate 1. Transmission and reflection spectra detailsare shown in FIG. 10. As with other embodiments herein, the TCC EMIfilter coating 30 provides the following functions/advantages: reducesdamage from EMI radiation through highly conductive Ag layers, blocksignificant amounts of NIR and IR radiation from outdoor sunlight toreduce panel temperature, and enhances contrast ratio through reducedreflection.

Referring to FIGS. 11-13, another example of this invention is similarto the embodiments of FIGS. 1-10, but also includes an extra dye(es)based absorption layer(s) to reduce transmission at about 595 nm (asshown in FIG. 11) to improve color neutrality for plasma displayapplications. In certain example embodiments, the dye is for absorbingat selected wavelength ranges, but not other ranges. For example incertain example embodiments, the dye may absorb light proximate 595 nm(e.g., see FIG. 11) in order to improve color characteristics of PDPdevices. The dye inclusive layer (not shown) can be introduced into oneor more locations, such as between AR coating 50) and substrate (1), orbetween TCC 30 and substrate 1, or between TCC 30 and the glue layer, orembedded in the glue layer or substrate(s) 1 (see FIGS. 6-8). Theoptical performance of an example of this dye inclusive embodiment forPDP devices is shown in FIG. 12, and transmission and reflection spectraof an example of this embodiment are shown in FIG. 13. In this coverglass structure, the TCC coating 30 provides the following functions:block the emitting of EMI radiation from plasma panel by highlyconductive Ag layers, block NIR and IR radiation from sunlight to reducepanel temperature for outdoor usage, enhance contrast ratio throughreduced reflection, and block the emitting of NIR (850-950 nm) radiationfrom plasma panel to avoid the interference to nearby electronics.

In view of the above, it is clear that EMI filters for PDPs may use atransparent conductive coating (TCC) for EMI and NIR blocking, and it isalso clear that it is desirable to have a low resistance ohmic contactbetween the EMI blocking layer and the grounded metal frame of the TV towhich the filter is attached. Also as noted above, although the use of aconductive black frit has been successfully implemented by the assigneeof the instant invention, further improvements are still possible.

Accordingly, certain example embodiments of this invention include a TCCEMI filter for PDP displays that does not require a conductive frame.Thus, it will be appreciated that such embodiments are less costly toproduce.

The TCC in an EMI filter may include multiple layers (e.g., three orfour layers) of silver between top and bottom dielectrics (insulators).The top and bottom layers are dielectrics (insulators) such as, forexample, tin oxide (SnO2 or other suitable stoichiometry) and SiNx. Anexample TCC EMI filter that has been successfully used in connectionwith designs that require bus bars is disclosed in FIG. 20. The layerstack in FIG. 20 is very similar to the layer stack shown in FIGS. 14-19of U.S. application Ser. No. 12/230,033, the entire contents of which isincorporated herein by reference and, indeed, exhibits similarproperties. The example layer stack in FIG. 20 of the instantapplication was heat treated at 600 degrees C. for 10 minutes. The layerstack in FIG. 20 has a visible transmission of at least about 60% (morepreferably at least about 62 or 63%), following HT. Additionally, thecoating of FIG. 20 has a sheet resistance (Rs) of no more than about 1.3or 1.2 ohms/square (more preferably of no more than about 1.0, and stillmore preferably of no more than about 0.90).

When the TCC EMI filter of FIG. 20 is mounted into a plasma TV without aconductive frame, the top dielectrics (e.g., SnO₂ and SiNx) prevent alow resistance contact between the metal frame in the television and theconductive silver layers in the TCC. Surprisingly and unexpectedly,however, despite this contact resistance, the filter of FIG. 20 has beenfound to pass EMI testing in most of the frequency range required forplasma television applications. That is, surprisingly and unexpectedly,despite this contact resistance, the filter of FIG. 20 has been found topass EMI testing throughout most of the frequency range of from about 30to 1000 MHz. Still more particularly, from about 60 to 1000 MHz, the EMIblocking capability is the same for filters with and without aconductive frame. The inventors of the instant application havedetermined, however, that it is in the frequency range of from about 30to 60 MHz that the EMI signal from the plasma television exceeds thelimit of 40 dBuV/m during standard CISPR-13 testing conditions. As isknown, the CISPR-13 standard is published by the InternationalElectrotechnical Commission, and describes the methods of measurementapplicable to sound and television receivers or associated equipment andspecifies limits for the control of disturbance from such equipment.

Certain example embodiments address the shortcomings of filters like theone shown in FIG. 20, e.g., by helping to ensure that EMI blockingrequirements are passed throughout the entire frequency range ofinterest. That is, certain example embodiments help ensure that EMIblocking requirements are passed throughout the entire frequency rangefrom about 30 to 1000 MHz. This may be accomplished in certain exampleembodiments by replacing the top dielectric layer(s) with a transparentconducting oxide (TCO). This arrangement is shown, for example, in FIG.21, which is a cross sectional view of an EMI filter for a plasmadisplay panel (e.g., PDP panel) that does not necessarily require aconductive bus bar or conductive frame according to an exampleembodiment of this invention. In other words, FIG. 21 is a crosssectional view of an EMI filter for a PDP that allows for a directconnection through, e.g., a conductive tape between the layer stackcomprising the EMI filter and the metal frame of the plasma television.In certain example embodiments, several alternating layers ofdielectrics and silver may be provided, with the TCO layer 2110 beingprovided over the top-most Ag layer. For example, three or four layersof silver may be provided. In the FIG. 21 example, first dielectriclayer(s) 2102 is provided nearest the surface of the glass substrate 1,a first silver layer 9 is provided over the first dielectric layer(s)2102, second dielectric layer(s) 2104 is provided over the first silverlayer 9, a second silver layer 19 is provided over the second dielectriclayer(s) 2104, third dielectric layer(s) 2106 is provided over thesecond silver layer 19, a third silver layer 29 is provided over thethird dielectric layer(s) 2106, fourth dielectric layer(s) 2108 isprovided over the third silver layer 29, a fourth silver layer 39 isprovided over the fourth dielectric layer(s) 2108, and a TCO layer 2110is provided over the fourth silver layer 39.

Certain example embodiments use zinc oxide doped with aluminum (ZnO:Al)as the TCO, applied to a thickness of about 30-40 nm and a resistivityof about 1-2 mohmcm. At this thickness, the absorption of the conductiveZnO:Al TCO is less than about 1%. Furthermore, because the refractiveindex of ZnO:Al is very close to that of the SnO₂ and SiNx dielectric,the optical transmittance and reflectance are virtually identical.

The ZnO:Al layer, as an overcoat, has sufficiently low resistivity tocreate a low resistance contact between the top Ag layer in the TCC andthe metal frame of the television. Electrical contact between the metaltelevision frame and top Ag layer of the TCC coating is sufficient forEMI blocking. Furthermore, the impedance between the top Ag layer andthe other Ag layers is very small, which is a result of the very thindielectric between the silver layers and the large area of the filter.

Although certain example embodiments have been described in connectionwith a TCO overcoat layer over the top Ag layer comprising ZnO:Al, otherTCO materials may be used in place of or in addition to ZnO:Al. Thus,TCO materials that may be used in connection with certain exampleembodiments include, for example, SnO:Sb, ITO, and TiOx:Nb. In general,materials having a refractive index of about 1.8 to 2.2 are preferable,although a refractive index of about 1.95-2.05 is more preferable, and arefractive index of 2.0 is still more preferable.

“Medium conductivity” is sufficient to ensure electrical contact to themetal frame of the television. Medium conductivity may be thought of asresistivity of between 1 mohmcm and 1 kohmcm. Electrical contact betweenthe metal TV frame and the top Ag layer of the TCC coating is sufficientfor EMI blocking. The frequency-dependent impedance (1/(ωC), where o) isthe radial frequency) between the top Ag layer and the other Ag layersis very small because of the very thin dielectric between the silverlayers and, the large area of the filter and the high frequency (30-1000MHz). Therefore, the top Ag layer can be considered shorted to the otherthree or four silver layers in the stack at the frequencies of interest.

For example, using the example embodiment shown and described in FIG. 22below, the capacitance between the top Ag layer and the Ag layer belowis about 475 microFarad for a 42 inch diagonal filter. The value isabout the same between the other Ag layers. At 30 MHz (e.g., the lowfrequency end of the EMI test) this translates into an impedance ofabout 1.1E-5 ohm between the Ag layers.

FIG. 22 is a cross sectional view of an EMI filter 2200 for a plasmadisplay panel (e.g., PDP panel) that does not necessarily require aconductive bus bar or conductive frame according to an exampleembodiment of this invention. The FIG. 22 example embodiment shows amore detailed view of the FIG. 21 example layer stack, along withoptional additional layers (including, for example, optional NiCrOxcontact layers 11, 21, 31, and 41). For example, a single SiNx Baselayer 2102 is provided as the dielectric closest to the surface of theglass substrate 1, whereas each of the other dielectrics include atleast SnO2 and SiNx layers. Accordingly, it will be appreciated that theFIG. 22 example embodiment is similar in structure to the FIG. 20example layer stack, except that the top-most dielectric layers fromFIG. 20 (the SnO2 and SiNx layers) are replaced with a single TCO layer2110 of or including one or more of the TCO's identified above—namely,ZnO:Al, SnO:Sb, ITO, and TiOx:Nb. However, the by replacing the top-mostdielectric layers from FIG. 20 (the SnO2 and SiNx layers) with a singleTCO layer 2110 (e.g., of or including one of the identified and/or otherTCO materials), typical EMI blocking requirements are passed throughoutthe entire frequency range from about 30 to 1000 MHz, e.g., by providinga low sheet resistance, even when no conductive frame is provided and/orwith the EMI filter 2200 directly contacts the metal frame of the plasmatelevision (via, e.g., conductive tape). It will be appreciated that theinclusion of one or more titanium oxide (e.g., TiO2 or other suitablestoichiometry) layer(s) is preferred, as titanium oxide layers ingeneral help increase visible transmission.

As noted above, the properties of the EMI filters of certain exampleembodiments that are capable of contacting the metal frames of plasmatelevisions, e.g., without conductive bus bars, frames, or the like, aresimilar to those shown and described in connection with FIG. 20. Thus,visible transmission may be at least about 60%, more preferably at leastabout 62% or 63%. However, sheet resistance may be kept the same, e.g.,so as to enable suitable EMI blocking requirements to be met throughoutthe entire frequency range of interest (e.g., from about 30 to 1000MHz). In this regard, sheet resistance preferable is below about 1ohm/sq., more preferably below about 0.9 ohm/sq., and still morepreferably below about 0.8 ohm/sq.

Using an Illuminate “C” test at a 2 degree observer angle, followingheat treating for 10 minutes at a temperature of 600 degrees C., thetransmission or Y value of an example was measured at 67.70%, glass sidereflection was measured at 5.16%, and front side reflection was measuredat 2.95%. As is desirable, the sheet resistance was low (below 1ohm/sq.). As designed, the layer stack was expected to have a sheetresistance of about 0.90 ohm/sq. Surprisingly and unexpectedly, however,post-heat treating, the EMI filter in the example had a sheet resistanceof about 0.77 ohm/sq.

The example embodiments described herein may lead to a number ofillustrative advantages. For example, filter manufacturing may besimplified, as the screen printing of the conductive frit no longer isnecessary. As described above in connection with the conductive blackfrit embodiments, certain example embodiments that implement a framelessTCC EMI filter also may result in a higher yield and lower manufacturingcosts. Indeed, the frameless TCC EMI filter of certain exampleembodiments may be coated on large glass sheets and then cut to size,thus saving time while reducing the number of process steps and wasteinvolved in the process.

Certain example embodiments advantageously also may result in improveddurability, e.g., depending on the choice of the TCO overcoat. Forexample, better environmental durability may allow the film laminationsteps to be reduced (e.g., only the AR film lamination may be required).Thus, a color correction film on the coating side may be eliminated incertain example embodiments, and color correction features instead canbe added to the pressure-sensitive adhesive (PSA) on the front ARlamination film. Durability tests include, for example, mechanicaldurability tests (e.g., passing brush-scratch tests with scores of 0 at150 strokes and scores of less than 1 at 300 strokes; passing tape pulltests with no delamination of the coating with the removal of atemporary protective film (TPF) or other tapes; etc), environmentaldurability tests (e.g., passing thermal cycling tests of two daysexposure in 24-hour cycles of temperatures ranging from about 20-100degrees F. while moving through the dew point, surviving two daysexposure with condensed relative humidity of about 100% at temperaturesof above 120 degrees F., sale-fog environmental durability tests, etc.),and/or the like.

While the materials shown for the various layers in the drawings arepreferred materials in certain example embodiments of this invention,they are not intended to be limited unless expressly claimed. Othermaterials may be used to replace materials shown in the drawings inalternative example embodiments of this invention. Moreover, certainlayers may be removed, and other layers added, in alternativeembodiments of this invention. Likewise, the illustrated thicknessesalso are not intended to be limiting unless expressly claimed.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A plasma display device comprising: a plasmadisplay panel (PDP); and an electromagnetic interference (EMI) filterprovided at a front portion of the plasma display panel, the EMI filterincluding an EMI coating supported by a glass substrate, the EMI coatingincluding the following layers moving away from the glass substrate: afirst high index layer having a refractive index (n) of at least about2.2 located on and directly contacting the glass substrate; a firstlayer comprising silicon nitride; a first layer comprising zinc oxide; afirst EMI shielding layer comprising silver contacting the first layercomprising zinc oxide; a first layer comprising an oxide of Ni and/or Crcontacting the first EMI shielding layer comprising silver; a firstlayer comprising metal oxide; a second layer comprising silicon nitride;a second layer comprising zinc oxide; a second EMI shielding layercomprising silver contacting the second layer comprising zinc oxide; asecond layer comprising an oxide of Ni and/or Cr contacting the secondEMI shielding layer comprising silver; a second layer comprising metaloxide; a third layer comprising silicon nitride; a second high indexlayer having a refractive index (n) of at least about 2.2; a third layercomprising zinc oxide; a third EMI shielding layer comprising silvercontacting the third layer comprising zinc oxide; a third layercomprising an oxide of Ni and/or Cr contacting the third EMI shieldinglayer comprising silver; and an overcoat layer comprising a transparentconducting oxide (TCO), wherein the EMI filter has a sheet resistance ofless than about 1 ohm, wherein the third EMI shielding layer comprisingsilver is thicker than each of the first and second EMI shielding layerscomprising silver.
 2. The plasma display device of claim 1, furthercomprising the following layers located, in order moving away from theglass, between the third layer comprising an oxide of Ni and/or Cr andthe overcoat layer comprising a TCO: a third layer comprising metaloxide; a fourth layer comprising silicon nitride; a fourth layercomprising zinc oxide; a fourth EMI shielding layer comprising silvercontacting the fourth layer comprising zinc oxide, the fourth EMIshielding layer comprising silver being thicker than each of the first,second and third EMI shielding layers comprising silver; and a fourthlayer comprising an oxide of Ni and/or Cr contacting the fourth EMIshielding layer comprising silver.
 3. The plasma display device of claim2, wherein the first high index layer comprises an oxide of titanium. 4.The plasma display device of claim 2, the first and second high indexlayers comprising an oxide of titanium.
 5. The plasma display device ofclaim 2, further comprising: a fourth layer comprising metal oxidelocated between the second layer comprising silicon nitride and thesecond layer comprising zinc oxide; and a fifth layer comprising metaloxide located between the fourth layer comprising silicon nitride andthe fourth layer comprising zinc oxide.
 6. The plasma display device ofclaim 5, wherein each said layer comprising metal oxide comprises anoxide of tin.
 7. The plasma display device of claim 1, wherein the glasssubstrate and the EMI coating combined have a visible transmission of atleast 55%.
 8. The plasma display device of claim 7, wherein the EMIfilter has a sheet resistance of less than about 0.9 ohm.
 9. The plasmadisplay device of claim 1, wherein the EMI filter directly contacts thePDP.
 10. The plasma display device of claim 1, wherein the TCO comprisesaluminum-doped zinc oxide.
 11. The plasma display device of claim 1,wherein the TCO comprises at least one of: antimony-doped tin oxide,indium tin oxide (ITO), and niobium-doped titanium oxide.
 12. The plasmadisplay device of claim 1, wherein the overcoat layer comprising the TCOis about 30-40 nm thick, and wherein the TCO has a refractive index ofabout 1.95-2.05.
 13. A plasma display device comprising: a plasmadisplay panel (PDP); and an electromagnetic interference (EMI) filterincluding an EMI coating supported by a glass substrate, the EMI coatingincluding the following layers moving away from the glass substrate: ananti-reflective coating; a first dielectric layer; a first EMI shieldinglayer comprising silver; a second dielectric layer; a second EMIshielding layer comprising silver a third dielectric layer; a third EMIshielding layer comprising silver a fourth dielectric layer; a fourthEMI shielding layer comprising silver; and an overcoat layer comprisinga transparent conducting oxide (TCO), wherein the glass substrate andthe EMI coating combined have a visible transmission of at least about60%, wherein the EMI filter has a sheet resistance of less than about0.9, wherein the TCO has a refractive index of about 1.95-2.05 whereinthe overcoat layer comprising the TCO is in electrical contact with anoverlapping metal frame of the plasma display panel.
 14. The plasmadisplay device of claim 13, wherein the second, third, and fourthdielectric layers each comprise a layer comprising silicon nitridesupported by a layer comprising tin oxide, and wherein the firstdielectric layer comprises a layer comprising silicon nitride.
 15. Theplasma display device of claim 14, wherein the TCO comprises at leastone of aluminum-doped zinc oxide, antimony-doped tin oxide, indium tinoxide (ITO), and niobium-doped titanium oxide.
 16. An EMI filter for aplasma display device comprising: an EMI coating supported by a glasssubstrate, the EMI coating including the following layers moving awayfrom the glass substrate: a first high refractive index layer; a firstlayer comprising silicon nitride; a first layer comprising zinc oxide; afirst EMI shielding layer comprising silver contacting the first layercomprising zinc oxide; a first layer comprising an oxide of Ni and/or Crcontacting the first EMI shielding layer comprising silver; a firstlayer comprising metal oxide; a second layer comprising silicon nitride;a second layer comprising zinc oxide; a second EMI shielding layercomprising silver contacting the second layer comprising zinc oxide; asecond layer comprising an oxide of Ni and/or Cr contacting the secondEMI shielding layer comprising silver; a second layer comprising metaloxide; a third layer comprising silicon nitride; a third layercomprising zinc oxide; a third EMI shielding layer comprising silvercontacting the third layer comprising zinc oxide; a third layercomprising an oxide of Ni and/or Cr contacting the third EMI shieldinglayer comprising silver; a third layer comprising metal oxide; a fourthlayer comprising silicon nitride; a fourth layer comprising zinc oxide;a fourth EMI shielding layer comprising silver contacting the fourthlayer comprising zinc oxide; a fourth layer comprising an oxide of Niand/or Cr contacting the fourth EMI shielding layer comprising silver;and an overcoat layer comprising a transparent conducting oxide (TCO),wherein the EMI filter has a sheet resistance of less than about 1,wherein the overcoat layer comprising the TCO is about 30-40 nm thick,and wherein the TCO has a refractive index of about 1.95-2.05 whereinthe overcoat layer comprising the TCO is adapted to be in electricalcontact with an overlapping metal frame of the plasma display device,and wherein the fourth EMI shielding layer comprising silver is thickerthan at least two of the first, second and third EMI shielding layerscomprising silver.
 17. The EMI filter of claim 16, further comprising asecond high refractive index layer, the second high refractive indexlayer being located between the second and third EMI shielding layers,wherein the first and second high refractive index layers comprises anoxide of titanium.
 18. The EMI filter of claim 17, further comprising: afourth layer comprising metal oxide located between the second layercomprising silicon nitride and the second layer comprising zinc oxide;and a fifth layer comprising metal oxide located between the fourthlayer comprising silicon nitride and the fourth layer comprising zincoxide, wherein each said layer comprising metal oxide comprises an oxideof tin.
 19. The EMI filter of claim 16, wherein the glass substrate andthe EMI coating combined have a visible transmission of at least 60%.20. The EMI filter of claim 16, wherein the EMI filter has a sheetresistance of less than about 0.9.
 21. The EMI filter of claim 16,wherein the TCO comprises at least one of: aluminum-doped zinc oxide,antimony-doped tin oxide, indium tin oxide (ITO), and niobium-dopedtitanium oxide.